This paper aims to investigate the air pollution issues in Hanoi – one of the most air polluted cities in the world in recent years – on residents’ and foreign visitors’ perceptions and how their trust in the local government to establish a joint funding mechanism to mitigate air pollution in Hanoi. Such information is fundamental in order to establish an effective and efficient program to improve air quality not only in Hanoi, but also in many cities around the world. We employ a random stratified approach coupled with the contingent valuation survey and an interval regression model over a sample of 475 residents and 75 foreigners. We found that public trust is relatively low in Hanoi. Almost all respondents in the city (95%) agreed air pollution is getting worse and poor air quality severely impacts their health and increases their healthcare expenses. Over 93% of respondents claimed an urgency to mitigate air pollution in the city, but the income shares for such mitigation activities are relatively small (only 0.4–0.5% ($4.6-$6) of their household monthly incomes). Many also refuse to make any contributions because their trust in the public sector to use such monetary contributions is low. We suggest that the local government may need to improve transparency and outline a clear plan with all cash inflow and outflow information provided on a website, enabling public verification, if they expect high contributions from the private sector to share the burden.